Related Experiment Video
Updated: Sep 13, 2026

Experimental Methods for Spin- and Angle-Resolved Photoemission Spectroscopy Combined with Polarization-Variable Laser
Published on: June 28, 2018
Imaging topological polar structures in marginally twisted 2D semiconductors
Thi-Hai-Yen Vu1, Daniel Bennett2,3, Gayani Nadeera Pallewela4
1School of Physics and Astronomy, Monash University, Clayton VIC 3800, Australia.
Abstract:
Moiré superlattices formed in van der Waals heterostructures by twisting, lattice mismatch and strain present an opportunity for creating metamaterials with unique properties absent in the individual layers. Ferroelectricity for example, arises from broken inversion symmetry in twisted and strained bilayers of 2D semiconductors with stacking domains of alternating out-of-plane polarization. However, the individual contributions of twist and strain to the formation of topological polar nanostructures remain unclear and experimentally challenging to resolve. Inversion symmetry breaking is predicted to generate in-plane polarization along the domain walls, forming topologically non-trivial Bloch-type merons (half-skyrmions) in twisted systems and Néel-type merons in strained systems. Here we utilize angle-resolved vector piezoresponse force microscopy to spatially resolve polarization components and topological polar nanostructures in marginally twisted bilayer WSe2, providing experimental evidence of topologically non-trivial meron/antimeron structures. This approach can be used to distinguish Bloch-type, Néel-type and hybrid structures, allowing us to quantify the separate contributions of strain and twist in a moiré superlattice, opening pathways for exploring twist-induced topology in engineered nano-devices.
Related Concept Videos
Biasing of Metal-Semiconductor Junctions
In Schottky junctions, where the semiconductor is n-type, applying a positive voltage to the metal relative to the semiconductor reduces its Fermi...
Dielectric Polarization in a Capacitor
Potential Due to a Polarized Object
Electrostatic Boundary Conditions in Dielectrics
Consider a case where both the mediums across a boundary are two different dielectric materials. Recall that the electric field and electric displacement are proportional and related through the material's permittivity.
Equipotential Surfaces and Conductors
Oriented Surfaces

